using System;

using Org.BouncyCastle.Asn1;

namespace Org.BouncyCastle.Asn1.Cms
{
	public class KekIdentifier
		: Asn1Encodable
	{
		private Asn1OctetString		keyIdentifier;
		private DerGeneralizedTime	date;
		private OtherKeyAttribute	other;

		public KekIdentifier(
			byte[]              keyIdentifier,
			DerGeneralizedTime  date,
			OtherKeyAttribute   other)
		{
			this.keyIdentifier = new DerOctetString(keyIdentifier);
			this.date = date;
			this.other = other;
		}

		public KekIdentifier(
			Asn1Sequence seq)
		{
			keyIdentifier = (Asn1OctetString) seq[0];

			switch (seq.Count)
			{
			case 1:
				break;
			case 2:
				if (seq[1] is DerGeneralizedTime)
				{
					date = (DerGeneralizedTime) seq[1];
				}
				else
				{
					other = OtherKeyAttribute.GetInstance(seq[2]);
				}
				break;
			case 3:
				date  = (DerGeneralizedTime) seq[1];
				other = OtherKeyAttribute.GetInstance(seq[2]);
				break;
			default:
				throw new ArgumentException("Invalid KekIdentifier");
			}
		}

		/**
		 * return a KekIdentifier object from a tagged object.
		 *
		 * @param obj the tagged object holding the object we want.
		 * @param explicitly true if the object is meant to be explicitly
		 *              tagged false otherwise.
		 * @exception ArgumentException if the object held by the
		 *          tagged object cannot be converted.
		 */
		public static KekIdentifier GetInstance(
			Asn1TaggedObject obj,
			bool explicitly)
		{
			return GetInstance(Asn1Sequence.GetInstance(obj, explicitly));
		}

		/**
		 * return a KekIdentifier object from the given object.
		 *
		 * @param obj the object we want converted.
		 * @exception ArgumentException if the object cannot be converted.
		 */
		public static KekIdentifier GetInstance(
			object obj)
		{
			if (obj == null || obj is KekIdentifier)
				return (KekIdentifier)obj;

			if (obj is Asn1Sequence)
				return new KekIdentifier((Asn1Sequence)obj);

			throw new ArgumentException("Invalid KekIdentifier: " + obj.GetType().Name);
		}

		public Asn1OctetString KeyIdentifier
		{
			get { return keyIdentifier; }
		}

		public DerGeneralizedTime Date
		{
			get { return date; }
		}

		public OtherKeyAttribute Other
		{
			get { return other; }
		}

		/**
		 * Produce an object suitable for an Asn1OutputStream.
		 * <pre>
		 * KekIdentifier ::= Sequence {
		 *     keyIdentifier OCTET STRING,
		 *     date GeneralizedTime OPTIONAL,
		 *     other OtherKeyAttribute OPTIONAL
		 * }
		 * </pre>
		 */
		public override Asn1Object ToAsn1Object()
		{
			Asn1EncodableVector v = new Asn1EncodableVector(keyIdentifier);
			v.AddOptional(date, other);
			return new DerSequence(v);
		}
	}
}

